Deforestation:
The conversion of forest to another land use or the long-term reduction of
the tree canopy cover below a 10 percent threshold. Deforestation implies
the long-term or permanent loss of forest cover and its transformation
into another land use.

People have
been deforesting the Earth for thousands of years, primarily to clear land
for crops or livestock.

Annual change in forest area by region in
millions of hectares per year, 1990-2010. There is a continued trend
towards expansion in Europe, while large-scale afforestation in China of
between 2 and 3 million hectares per year is contributing to net gains in
Asia. The rate of deforestation is decreasing in some countries, such as
Brazil and Indonesia. However, net losses remain significant in South
America and Africa despite this reduction. Severe drought and forest fires
have exacerbated forest losses in Australia since 2000.
Source: FAO (2010)

Direct causes
of deforestation are agricultural expansion, wood extraction (e.g.,
logging or wood harvest for domestic fuel or charcoal), and infrastructure
expansion such as road building and urbanization. Rarely is there a single
direct cause for deforestation. Most often, multiple processes work
simultaneously or sequentially to cause deforestation.

The world’s total forest
area is just over 4 billion hectares, corresponding to 31 percent of the
total land area or an average of 0.6 ha per capita. The five most
forest-rich countries (the Russian Federation, Brazil, Canada, the United
States of America and China) accounted for more than half of the total
forest area. Ten countries or areas had no forest at all and an additional
54 had forest on less than 10 percent of their total land area.

At present the rate
of deforestation and loss of forest from natural causes is still
alarmingly high, but is slowing down. At the global level, it
decreased from an estimated 16 million hectares per year in the 1990s to
around 13 million hectares per year in the last decade.

At the same time,
afforestation and natural expansion of forests in some countries and areas
reduced the net loss of forest area significantly at the global level. The
net change in forest area in the period 2000–2010 was estimated at -5.2
million hectares per year (an area about the size of Costa Rica), down
from -8.3 million hectares per year in the period 1990–2000. However, most
of the loss of forest continued to take place in countries and areas in
the tropical regions, while most of the gain took place in the temperate
and boreal zones, and in some emerging economies.

Impacts of
Deforestation: Biodiversity Impacts

Although tropical forests
cover only about 7 percent of the Earth’s dry land, they probably harbor
about half of all species on Earth. Many species are so specialized to
microhabitats within the forest that they can only be found in small
areas. Their specialization makes them vulnerable to extinction. In
addition to the species lost when an area is totally deforested, the
plants and animals in the fragments of forest that remain also become
increasingly vulnerable, sometimes even committed, to extinction. The
edges of the fragments dry out and are buffeted by hot winds; mature
rainforest trees often die standing at the margins. Cascading changes in
the types of trees, plants, and insects that can survive in the fragments
rapidly reduces biodiversity in the forest that remains. People may
disagree about whether the extinction of other species through human
action is an ethical issue, but there is little doubt about the practical
problems that extinction poses.

First, global markets
consume rainforest products that depend on sustainable harvesting: latex,
cork, fruit, nuts, timber, fibers, spices, natural oils and resins, and
medicines. In addition, the genetic diversity of tropical forests is
basically the deepest end of the planetary gene pool. Hidden in the genes
of plants, animals, fungi, and bacteria that have not even been discovered
yet may be cures for cancer and other diseases or the key to improving the
yield and nutritional quality of foods—which the U.N. Food and Agriculture
Organization says will be crucial for feeding the nearly ten billion
people the Earth will likely need to support in coming decades. Finally,
genetic diversity in the planetary gene pool is crucial for the resilience
of all life on Earth to rare but catastrophic environmental events, such
as meteor impacts or massive, sustained volcanism.

Soil Impacts

With all the lushness and
productivity that exist in tropical forests, it can be surprising to learn
that tropical soils are actually very thin and poor in nutrients. The
underlying “parent” rock weathers rapidly in the tropics’ high
temperatures and heavy rains, and over time, most of the minerals have
washed from the soil. Nearly all the nutrient content of a tropical forest
is in the living plants and the decomposing litter on the forest floor.

Importance of Forests

Forests and air

Over 40 percent of the
world's oxygen is produced from the rainforests.

Forests contribute to
the balance of oxygen, carbon dioxide and humidity
in the air.

Forests and water

A tree releases 8-10
times more moisture into the atmosphere than the
equivalent area of the ocean.

Forests protect
watersheds which supply fresh water to rivers.

Loss of forests could
affect rainfall patterns globally, especially in food
growing regions in Latin America, the American mid-West and Central
Asia.

Deforestation leads to
soil erosion and rivers being silted, which reduces
access to clean wate

Forests and biodiversity

Forests are home to over
80% of terrestrial biodiversity.

In the Amazon basin
alone, more than 1,300 species of forest plants are
used for medicinal or cultural purposes.

12% of the world’s
forests are designated for the conservation of biological
diversity (FRA 2010).

Deforestation of closed
tropical rainforests could account for the loss of as
many as 100 species a day.

Forests build resilience
to natural disasters

Nearly 330 million
hectares of forest are designated for soil and water
conservation, avalanche control, sand dune stabilization,
desertification
control or coastal protection. (FRA 2010)

Mangrove forests act as
a barrier against tsunamis, cyclones and
hurricanes.

‘Green Wall for the
Sahara’ The European Union and African Union are
implementing a project to build a ‘green wall’ of trees across the
Sahara
to push back desertification and to secure agriculture and livelihoods
in
the sahelo-saharan zone.

Forests and land

Forests cover 31% of
global land area

Forests and tree cover
combat land degradation and desertification by stabilizing soils,
reducing water and wind erosion and maintaining nutrient cycling in
soils.

Forests are a key part of
the climate change solution

The carbon in forests
exceeds the amount of carbon currently in the atmosphere. FRA 2010
estimates that the world’s forests store 289 gigatonnes (Gt) of carbon
in their biomass alone.

Forests offer the
quickest, most cost-effective and largest means of curbing global
emissions. It would save the world approximately $3.7 trillion between
2010 and 2200 if we halve greenhouse gas emissions (The Stern Review
on the Economics of Climate Change, 2006).

Healthy forests, healthy
people

Tropical forests provide
a vast array of medicinal plants used in healing and healthcare, worth
an estimated $108 billion a year.

More than a quarter of
modern medicines originate from tropical forest plants.

Given that more than 1
billion hectares of degraded areas throughout the world are suitable for
forest landscape restoration, community-based forest management could be
woven into other existing rural economic activities.

DEFORESTATION IN BRAZIL:
60-70 percent of deforestation in the Amazon results from cattle ranches
while the rest mostly results from small-scale subsistence agriculture.
Despite the widespread press attention, large-scale farming (i.e.
soybeans) currently contributes relatively little to total deforestation
in the Amazon. Most soybean cultivation takes place outside the rainforest
in the neighboring cerrado grassland ecosystem and in areas that have
already been cleared. Logging results in forest degradation but rarely
direct deforestation. However, studies have showed a close correlation
between logging and future clearing for settlement and farming

In the Brazilian state of
Mato Grosso, verdant green Amazon Rainforest is broken up by broad tracts
of pale green and tan deforested land. In 2005, the government of Brazil
said that 48 percent of Amazon deforestation that took place in 2003 and
2004 occurred in Mato Grosso.

The transformation from
forest to farm is evident in the photo-like images, taken by the Moderate
Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
The top image was taken on June 28, 2006, while the middle image is from
June 17, 2002. The bottom map shows the difference in deforested areas
over the time period, with some of the largest cleared areas marked in
red. On this map, areas that were non-forested (either naturally or
already deforested) in 2002 are light gray, while areas that remained
forested in 2006 are darker gray.

Although some deforestation
is part of the country’s plans to develop its agriculture and timber
industries, other deforestation is the result of illegal logging and
squatters. The Brazilian government uses MODIS images such as these to
detect illegal deforestation. Because the forest is so large and is
difficult to access or patrol, the satellite images can provide an initial
alert that tells officials where to look for illegal logging.

These images were produced
by the MODIS Rapid Response Team, which provides both the 2006 and 2002
images in a variety of resolutions, including MODIS’maximum resolution of
250 meters per pixel.

The state of Rondônia in
western Brazil — once home to 208,000 square kilometers of forest (about
51.4 million acres), an area slightly smaller than the state of Kansas —
has become one of the most deforested parts of the Amazon. In the past
three decades, clearing and degradation of the state’s forests have been
rapid: 4,200 square kilometers cleared by 1978; 30,000 by 1988; and 53,300
by 1998. By 2003, an estimated 67,764 square kilometers of rainforest—an
area larger than the state of West Virginia—had been cleared.

August 2, 2010

By the start of this
satellite time series from the Moderate Resolution Imaging
Spectroradiometer (MODIS) on NASA’s Terra satellite, the frontier had
reached the remote northwest corner of Rondônia. Intact forest is deep
green, while cleared areas are tan (bare ground) or light green (crops,
pasture, or occasionally, second-growth forest). Over the span of eight
years, roads and clearings pushed west-northwest from Buritis toward the
Jaciparaná River. The deforested area along the road into Nova Mamoré
expanded north-northeast all the way to the BR-346 highway.

Deforestation follows a
fairly predictable pattern in these images. The first clearings that
appear in the forest are in a fishbone pattern, arrayed along the edges of
roads. Over time, the fishbones collapse into a mixture of forest
remnants, cleared areas, and settlements. This pattern follows one of the
most common deforestation trajectories in the Amazon. Legal and illegal
roads penetrate a remote part of the forest, and small farmers migrate to
the area. They claim land along the road and clear some of it for crops.
Within a few years, heavy rains and erosion deplete the soil, and crop
yields fall. Farmers then convert the degraded land to cattle pasture, and
clear more forest for crops. Eventually the small land holders, having
cleared much of their land, sell it or abandon it to large cattle holders,
who consolidate the plots into large areas of pasture.

Some areas of Rondonia, Brazil, have been almost completely deforested in
just 6 years. This pair of images uses a scale, or index, of vegetation to
compare forest area in 2000 to 2006 at the full resolution (15 meters per
pixel) of the Advanced Spaceborne Thermal Emission and Reflection
Radiometer (ASTER) instrument. Cleared areas (tan) spread from roads cut
through the forest (green), a pattern of deforestation typical in
Rondonia. (Maps by Robert Simmon, based on ASTER data.)

This map shows percent forest cover in eastern Democratic Republic of the
Congo. Red areas, expanding outward from the town of Mambasa, show
deforestation between 1990 and 2000. (Map by Robert Simmon, based on data
from the Decadal Forest Change Mapping Project.)

Rondônia is part of the Brazilian Amazon, on the border with Bolivia. It
is one of the peripheral areas undergoing expansion within Amazonia,
growing from about half a million inhabitants in 1980 to more than 1.5
million in 2009. Within the Brazilian Amazon, Rondônia has the highest
deforestation rate. It reached more than 34 percent in 2008, a drastic
increase from 1978 when less than 2 percent had been cut. The principal
causes of deforestation in the Amazon as a whole — and especially in
Rondônia — are population growth due to government-promoted immigration,
the growth of the wood-products industry in conjunction with the expansion
of the road network, and burning for management of pastureland and
agricultural fields.

Data compiled from The
British Antarctic Study, NASA, Environment Canada, UNEP, EPA and
other sources as stated and credited Researched by Charles
Welch-Updated daily This Website is a project of the The Ozooe Hole
Inc. http://www.theozonehole.com